Spinning solutions of vinyl chloride polymer in a solvent mixture of tetrahydrofurane and a nitrile



Patented Nov. 4, 1952 POLYMER IN A SOLVENT MIXTURE OF TETRAHYDROFURANEAND A NITRILE Erwin Heisenberg, Erlenbach-on-the-Main, and

Johannes Kleine, Munchen, Germany, assignors to VereinigtcGlanzstofif-Fabriken A. G., Wuppcrtal-Elberfeld, Germany No Drawing.Application'April 18, 1951, Serial -No. 221,714. In Germany August '18,1949 1 The present invention relates to liquid compo- 7 Claims. (01.260-303) sitions of matter, more especially solutions of polymers and/orcopolymers of vinyl chloride, M

which canbe spun to form threads and the like,

and which can be cast to form films. The invention relates further tothe production of such compositions and to the production of spun filaments with the aid thereof.

It has been proposed in the literature to dissolve polyvinyl chloride intetrahydrofurane and to work up these solutions into artificial threads.In this way, however, solutions are obtained of gluey consistency whichin practice cannot bespun.

Attempts have been made to overcome this disadvantage by subjecting thepolyvinyl chloride to an additional chlorination before dissolv ing it.This does give an increased solubility, for example even in acetone, butsuch a procedure means that the process involves an additional step. i'Even when the spinning properties are improved byheating the solutionsbefore spinning, for example to 50 C., and even when spinning is carriedout at this temperature, a satisfactory result is not obtained.Moreover, when working in the vicinity of the boiling point of thesolvent, bubbles are readily formed in the thread which considerablyreduces its quality. The thread is also embrittled by spinning at raisedtemperature so that optimum strength values are no longer obtained uponsubsequent stretching. A whole series of lactones and lactams have beenproposed in the patent literature which are said to be suitable assolvents for high polymers and copolymers of vinyl compounds.Suchsolvents or mixtures thereof, however, do notgive solutions whichcan be used to spin threads of high quality. l

In order to increase the solubility of polylvinyl chloride, certainquantities of other vinyl compounds have been added duringpolymerization. It has injfact been possible to increase the solubilityof polyvinyl chloride in this way, butaonly at the cost of impartinginferior textile properties to the spun threads obtained therefrom.

A primary objectof the present invention is the embodiment of spinningsolutions which are free of the prior art defects as hereinbefore seterties, and which can be further conditioned to p produce superiortextile fibers." Theseobjectsarc 2 achieved in a simple way according tothe present invention, which production of good spinning solutions ofvinyl chloride polymers and copoly-.- mers from which high qualitythreads can be spun, by incorporating into the tetrahydrofurane, whichis used as solvent, certain quantitles of adipic acid dinitrile. Theresults thus achieved are surprising because neither tetrahydrofuranenor adipic acid dinitrile by itself gives vinyl chloride polymersolutions which can be satisfactorily spun. The .favorable influence ofadipic acid dinitrile becomes perceptible even on addition of about 10%by weight, relative to the weight of the solvent mixture, and increaseswith increasing quantity of the addition. The effect begins to diminishonly when the adipic acid dinitrile becomes the predominant component ofthe mixture. A particularly favorable proportion of the two saidcompounds in the mixture is a proportion of one part by weight of adipicacid dinitrile to four parts by weight of tetrahydrofurane.

Moreover, admixture with" tetrahydrofurane according to the invention.produces a -fimd'a-=- mental change not only in the solvent power ofadipic acid dinitrile but also in the solvent power of other solventswhich have previously been proposed for polyacylonitrile but'which bythemselves cannot be used to give vinyl chloride polymer solutions whichcan be satisfactorily spun. Such compounds which can be used withtetrahydrofurane as solvents to give vinyl chloride polymer solutionswhich can be satisfactorily spun according to this invention compriseother nitriles and other chemical compound-s of analogous structure,such for example as:

- 1,2,3-tricyano-propane;

1,1,2-tricyano-propane; 1,2-dicyano-cyclobutane;1,3-dicyano-cyclobutane; 1,3,3,5-tetracyanopentane; 1,2,5-tric'yano=1Fhydroxy pentane; 1,2,3}!-tetracyano-cyclobutane;

e 3 1,2-dicyano-3-methyl-cyclobutane; fl-hydroxyglutaric acid dinitrile;a-hydroxyglutaric acid dinitrile; Diglycolonitrile;Thiodiglycolenitrile; fi-methyl-malonitrile;

Bis- (5, 3-dicyano-isopropyl) -ether; Bis- (fi-cyanoethyl) -etherBis-(B-cyanoethyl) -sulfide; etc.

Preferably the solvent mixture contains from to 50% by weight of theadditional solvent. In certain circumstances the upper limit can beexceeded since even then a certain improvement in solubility isobtained.

The examples given below describe in more detail individual mixtureswhich have particularly good properties due to the-nature and proportions of their ingredients. i

When more than one of the said additional substances are admixed withtetrahydrofurane, which is possible according to the'present. inven.tion, preferably the proportions'of the ingredie ents are maintainedwithin the above described limits,'the total quantity of the additional1sub.- stances lying within these limits.

The favorable effects in improving the solubility with the solventmixtures used according to the invention are obtained not only withpolyvinyl chloride but also with copolymers of vinyl chloride, forexample vinyl chloride-vinyl acetate copolymers, vinylchloride-vinylidene chloride copolymers, vinyl chloride-styrenecopolymers, vinyl chloride-vinyl acetate-vinylidene chloride copolymers,etc.

One of the most important advantages of solutions produced according tothe invention is that the solutions can be spun without dif culty atroom temperature to form artificial threads, artificial bristles and thelike, either bythe wet spinning; process or by the dry spinning process.

in this way tor -example artificial threads are obtained with a strengthof 2.5 to 3 grams/denier and tn i lls Q 5=25%. .Thesolutions are a serysu t bleior th producti n of m by cast- 113g, The solutionspreferably contain from about to about by weight of polymer.

The following examples describe, solely by way of illustration,presently preferred embodiments of the process of the invention.

Example 1 100 parts by weight of-polyvinyl chloride are introduced withstirring at 25 C. into a mixture of 100 parts by weight of adipic aciddinitrile and 400 parts by weight of tetrahydroiurane. The mixture isheated slowly to boiling while stirring constantly and, when the polymerhas entirely dissolved, is cooled again to room temperature (about 20C.) The resultant solution can be spun, for example through multieholestainless steel jets, into water; at .20? C.

Example 2 200 parts by weight of polyvinyl chloride are introduced withstirring at 20 C. intoaimixture of 150 parts by weight of glutaric aciddinitrile and 600 parts by weight of tetrahydrofurane. The thus-obtainedmixture is heated slowly to boiling with constant stirring and, whendissolution of the polymer is complete, is again cooled at 20 C. Theresultant solution can be made up into filaments, threads, bristles,fi1ms ,.etc.

Example 3 150 parts by Weight oi polyvinyl chloride are i t u withtirrin at 20C. into a mixture 4 of 150 parts by weight of succinonitrileand 600 parts by weight of tetrahydrofurane. Th thus obtained mixture isheated slowly to boiling with constant stirring and, when dissolution ofthe polymer is complete, is again cooled at 20 C. The resultant solutioncan be made up into filaments, threads, bristles, films, etc.

Example 4 chloride are introduced into a mixture of parts ofvsuccinonitrile and 500 parts by weight of tetrahydrofurane. The mixtureis heated, with stirring, untilcomplete solution is achieved, and

is thereupon cooled to room temperature (20 H After filtering, ifnecessary, the solution maybespun'into water at 25 C.

Example 5 100 parts by weight of polyvinyl chloride are introduced withstirring at 20 G. into a mixture of 60 parts by weight of glutaric aciddinitrile and 600 parts of tetrahydroiurane. The resultant mixture isheated to boiling and, when solution is complete, is cooled back to roomtemperature. The cooled solution may be used for spinning threads.

Example 6 parts by weight of polyvinyl chloride are introduced into amixture of 300 parts by weight of adiponitrile and 300 parts by weightof tetrahydrofurane, the mixture is then slowly heated to boiling, whileconstantly stirring, and after solution is complete, the solution iscooled to room temperature. The cooled and filtered solution may be usedin the spinning of threads.

In each of Examples 4, 5 and 6, the recited nitrile (succinonitrile,glutaric acid dinitrile, adiponitrile) may, with equivalent results, bereplaced by an equivalent quantity of malonitrile, fumaric aciddinitrile, diglycolonitrile, or 1,2-dicyanoe-cyclobutane, while.otherwise proceeding as, described in ,the respective example.

Havingthus disclosed the invention, what is claimed is;

1. A liquid composition of matter which can be spun to form threads andthe like and which can be cast to form films, comprising a vinylchloride polymer as solute in solution in tetrahydrofurane as solvent,said solvent having admixed therewith from about 10% to about 50% byweight of the mixture, of a nitrile which can dissolve polyacrylonitrilecompletely but which does not by itself give .vinyl chloride polymersolutions. which can be spun.

2. A liquid composition of matter which can be spun to form threads andthe like and which can be cast to form films, comprising a vinylchloride polymer. as solutein solution in tetrahydroiurane as solventsaid solvent having admixed therewith from about 10% to about 50% byweightof the mixture, of glutaric acid die nitrile.

3. A liquid composition of matter which can be spun to form threads andthe like and which can be cast to form films, comprising .a vinylchloride polymer as solute in solution in tetrahydrofurane as. solvent,said solvent havingadmixed therewith, as an additional solvent, anitrile, the proportion between additional solvent and tetrahydrofuranein the solvent mixture being about 1 :4, by weight.

4. A liquid composition of matter which can be s n' o torn; hrdsandthelike and whicncan be cast to form films, comprising a vinylchloride polymer as solute in solution in tetrahydrofurane as solvent,said solvent having admixed therewith, as an additional solvent,glutaric acid dinitrile, the proportion between additional solvent andtetrahydrofurane in the solvent mixture being about 1:4 by weight.

5. A liquid composition of matter which can be spun to form threads andthe like and which can be cast to form films, comprising a vinylchloride polymer as solute in solution in tetrahydrofurane as solvent,said solvent having admixed therewith, as an additional solvent,malonitrile, the proportion between additional solvent andtetrahydrofurane in the solvent mixture being about 1:4 by weight.

6. A liquid composition of matter which can be spun to form threads andthe like and which can be cast to form films, comprising a vinylchloride polymer as solute in solution in tetra- 20 cinonitrile, theproportion between additional solvent and tetrahydrofurane in thesolvent mixture being about 1:4 by weight.

7. A liquid composition of matter which can be spun to form threads andthe like and which REFERENCES CITED UNITED STATES PATENTS Name Date HamNov 7, 1950 Number

1. A LIQUID COMPOSITION OF MATTER WHICH CAN BE SPUN TO FORM THREADS ANDTHE LIKE AND WHICH CAN BE CAST TO FORM FILMS, COMPRISING A VINYLCHLORIDE POLYMER AS SOLUTE IN SOLUTION IN TETRAHYDROFURANE AS SOLVENT,SAID SOLVENT HAVING ADMIXED THEREWITH FROM ABOUT 10% TO ABOUT 50% BYWEIGHT OF THE MIXTURE, OF A NITRILE WHICH CAN DISSOLVE POLYACRYLONITRILECOMPLETELY BUT WHICH DOES NOT BY ITSELF GIVE VINYL CHLORIDE POLYMERSOLUTIONS WHICH CAN BE SPUN.